Changes in the brain in early infancy can predict diagnosis of autism at age of 2 years in kids who have older autistic siblings, according to findings of a new autism study.

A team of researchers scanned brains of children facing “high” risk of developing autism because of an older brother or sister’s diagnosis. They also scanned brains of kids who had no family history of the devastating disease.

The researchers conducted MRIs when the kids were age 6, 12 and 24 months old, and administered a test at age of 2 years. They measured total brain volume and cortex thickness. Then they compared changes over time with outcomes such as severity score on the scale of autism diagnostic and scores on social measures.

They discovered rapid cortical surface growth from age 6 to 12 months and found that it was a predecessor of an increase in brain volume in high-risk kids diagnosed with autism at age 24 months. The researchers were able to predict diagnosis of autism in 81 per cent of the high-risk kids who were eventually diagnosed with autism.

University of Washington Prof. Annette Estes, who co-authored the study, said, “Typically, the earliest we can reliably diagnose autism in a child is age 2 … But in our study, brain imaging biomarkers at 6 and 12 months were able to identify babies who would be later diagnosed with ASD.”

The findings of the new study, which doesn’t suggest anything about causation of the disease, published in the most recent edition of the journal Nature.